A prologue, set after World War II, details an American warship in Manchuria being overrun by ghostly apparitions, causing the death of the crew.
In the present day, brothers Alex and Brad are preparing for a diving expedition into the South Pacific Ocean alongside Alex's girlfriend, Julia, Julia's brother, Conrad, and the ship's skipper, Fliss, Alex and Julia seek out to find a World War II wreck plane rumoured to have crashed. Meanwhile, a group of fishermen consisting of Danny, Junior, and leader Olson crash into Fliss' boat, the Duke of Milan. After the expedition group celebrate, the fishermen ambush the boat and take the protagonists hostage; Brad may optionally remain in hiding. Conrad attempts to steal the fishermen's speedboat, which he can either successfully do so and flee, remain captured, or be killed in the attempt. Olson discovers the coordinates of a seemingly hidden treasure named Manchurian Gold and seeks out to find it with the Duke crew in his captivity.
